Taper upper courses of brick?

[Harpist]

Howdy folks,

Greatings from North Idaho on the shores of Lake Pend Oreille!

I'm in the process of laying out the oven dome and I had a question about the upper courses of fire brick. I am doing a hemispherical 40" dome using a styrofoam form.

Are the upper courses of brick generally tapered on the sides to get a snug fit (and I assume greater strength) or should I just use straight cuts and have an angled gap between each brick in the course?

If they are not tapered I would guess that I should make the width of the bricks smaller as I go higher on the dome (otherwise the angled gap between brick would get larger with each course).

It has been many years since I have done brick work (I do a fair amount of stone work) and never a dome. I am doing my brick cuts with a 7" Ryobi tile saw.

Thanks for any and all assistance.

Good Roads

Harpist